The technique entitled, “Intubation”, which includes inserting a cuffed or cuff less Endo Ttracheal Tube (ETT) into the respiratory channel (i.e., the trachea) of the patient, is used to promote mechanical ventilation in surgical or intensive care settings. It is needless to mention that the cuffles tubes mentioned above are used in the case of little children.
This method is also used as a means in keeping the respiratory channels open, which is of vital importance during surgeries. During the intubation, the ETT and the cuff(s) act as foreign objects in the respiratory passages, leading to the intolerance of the patients and consequently to reactions in the air passages.
Extubation, or in other terms removal of the ETT(s) at the end of the anesthesia of the patient, also leads to reactions that are technically called “Emergence reactions” including hypertension, tachycardia, dysrythmia, increases in IOP (Intra Ocular Pressure), ICP (Intra Cranial Pressure), bucking or straining, bronchospasm, laryngospasm, glottic spasm and so on that can lead to myocardial ischemia, defective arterial oxygenation, and vomiting, which may in turn lead to serious repercussions endangering the life of the patient. Other disadvantages resulting from the application of the presently available ETTs include tearing of stitches and bleeding as a result of bucking or straining by the patient. The intolerance of the ETTs can also lead to self-extubation of these devices by the patients that may lead to a critical situation, which if not attended promptly and urgently, can lead to the catastrophic outcomes. The main reason behind such emergence reactions is the intolerance of the ETT owing to lighter planes of anesthesia towards the end of surgery and prior to extubation. The increase in blood pressure, pulse rate, IOP, and/or ICP of the patients, suffering from underlying coronary artery disease or who have undergone eye or intracranial surgeries and pregnancy induced hypertension (PIH) may lead to disastrous outcomes.
Inadvertent or unanticipated extubation may lead to laryngospasm, bronchospasm, hypoxia and/or pulmonary edema commonly encountered in all patients especially those with hyper reactive airway diseases or bronchial asthma. Also post surgical stridor, sore throat and irritable cough may also be caused due to the application of the cuffed ETTs. Many methods have been used to overcome or at least lessen these reactions in patients, which include systemic administration of opioids, sedatives, hypnotics, β blockers, Na nitroprussid local anesthetics, topically applied local anesthetics, intra-cuff administration of lidocaine, intra-cuff administration of warmed and alkalinized lidocaine, and new designs of ETT(s) such as Mallinckrodt ET, for applying local anesthetics to tracheal mucosa, using 10% lidocaine and etidocaine sprays through some channels on the ETT and the LITA ETT.
None of these methods have however been definitely and completely successful and safe in overcoming the problems mentioned above.
Tolerance of the ETTs in conscious patients with intact airway reflexes of the entire respiratory system (e.g. in the intensive care units), is almost impossible. Thus opioids and other anesthetic drugs are administered so as to increase the threshold of tolerance of the tubes by the patients and prevent self extubation and/or other possible reflexes. This however leads to a prolonged stay in the ICU and thus results in an increased risk of complications such as infections, pressure sores and narrowing of the wind pipe—the trachea.